Display technology has really been advancing and 3D is starting to become very commonplace, but with manufacturers using different technologies, things can get confusing quickly. We’re here to help you decide which to choose for your upcoming holiday purchases.

Image cropped from some wallpaper we had. Source unknown.

So, You’re Considering 3D

So the holiday season is upon us, and you’re considering getting or gifting a new display. 3D is everywhere now, and it’s getting cheaper, so it’s easy to just add that to the list of features you want. The world of 3D TVs and monitors is pretty wild and complicated, however. We’ve come a long way from anaglyph 3D and red/cyan glasses, and there are three main technologies that are competing right now. Each has its own advantages and disadvantages and this guide should help you decide which is best for you.

We’ve done our research here and looked at hundreds of monitors and TVs to get real first-hand experience, but one thing that’s especially true about 3D is that everyone sees things slightly differently. That being said, we’ve also done our best to explain some things on the fringes of consumer products – things that aren’t everywhere yet, but are coming soon – so you’ll know what to look for in case you decide to hold off on your purchase.

Basic 3D: How It Works

In order to understand why 3D is the way it is, it’s important to understand how it works. 3-dimensional images are really attempts to imitate how physical objects are seen be our eyes.

Each of our two eyes focuses on an object in front of us, and since our eyes are set a small distance apart, they see two different images. Try focusing on something a foot or two away from you with one eye closed, then switch to the other eye. Notice how the perspective changes? Well your brain sort of puts those images together so they are in focus, and things that are closer or farther away are not in focus.

All 3D technology essentially shows you two different sets of images to try to replicate this effect. Where they differ is in how they present them to you, and those differences can lead to some drastic effects. The three main types of 3D technology used in modern displays are Passive, Active Shutter, and Glasses-Free.

Disclaimer

The inspiration for this article came from LG’s booth at BlizzCon. LG was kind enough to sponsor us for the event, as well as give us a breakdown of their newest 3D monitor technology below. There are quite a few different things going on in the world of home 3D technology, and we thought it’d be a great idea to show you the ins and outs of everything. We include a lot of our opinions in the section on emerging technology below, and they cover LG’s technology. You don’t have to take our word for it, of course, and we strongly encourage you to take a look at everything yourself even if you agree with our opinions. Only your eyes will tell you what’s better or worse.

Passive 3D

Passive 3D has been around for a while now. It’s a glasses-based technology that works by polarization of light, something that it has in common with good sunglasses. Light travels in waves, and in most cases, they are polarized. This means that the direction in which the waves oscillate are perpendicular to the direction they travel in. Picture how snakes slither left and right as they move forward and you’ve got the idea. Now, light can slither in all sorts of directions, not just side-to-side. Polarized sunglasses reduce glare by filtering light horizontally (since most light reflected off of flat surfaces is horizontally polarized). The vertically-oriented light waves can still pass through, so you can still see, but the overall dimming effect is still there.

A few years ago, passive 3D technology used linearly polarized light the same way as above. Two images are shown on the same screen, one using horizontally-polarized light, and the other using vertically polarized light. While watching a movie, one eye only sees the horizontal image and the other only sees the vertical one. Newer technology has changed a bit, but more on that later.

Advantages

Cheap/Easy to get glasses

Doesn’t require super-powerful graphics card

Full frame rate

The nice part about passive 3D is that the glasses are cheap. Most TVs and monitors come with a pair or two, and extra ones can be bought cheaply or borrowed* from movie theaters. The other nice part is that your computer won’t need an expensive upgrade in order to display video that’s encoded in this way. It’s all really built into the display. Lastly, you’re getting the full frame rate of your video. If your TV/monitor displays at 240 Hz, each eye is getting images at 240 Hz.

* How-To Geek does not condone theft or borrowing of property that does not belong to the user. You steal at your own risk.

Disadvantages

Glasses can severely dim the image

The biggest drawback is that, by nature of the mechanism, polarized glasses makes images darker. While this may not be so bad on a computer monitor you can increase the brightness on, it’s really huge setback for any kind of home theater set up at all. Seriously, this can really render home theaters’ 3D abilities useless. There are some changes that are occurring with passive 3D that mitigate this, though, but we’ll discuss that a bit later.

Active Shutter

Active shutter is newer than passive technology. Here, the glasses you use aren’t simple plastic filters; they’re battery-powered devices that are sensitively honed. What happens is your display alternates images from each of the two perspectives, and your glasses synchronize with the refresh rate. When the image for your right eye is displayed, the glasses use a shutter over your left eye. When the image for your left eye is displayed, the glasses move the shutter on your right eye. In this way, each eye is getting an image, and the it’s coming to each eye one-at-a-time in rapid alternation.

Advantages

Bright video

Great picture quality

Works well with multiple monitors

There’s a move for standardization

The images viewed by active shutter are bright and vivid, and the quality overall is pretty good. Because of how the technology works, each eye is getting half of the frame rate, so 240 Hz video means each eye is getting 120 frames per second. To be honest, though, it’s hard to notice, especially on higher-end TVs. Why? Well the bright and vivid picture make up for it, and since we’re talking about more frames than your eye can see anyway, it’s usually not a big deal. Your mileage may vary, however.

A big benefit is that the technology works very well with multiple monitors, which seems a little surprising when you consider how it works. It’s not that passive doesn’t work well, but active shutter somehow has a punch to it that’s hard to describe.

With these various 3D technologies all competing, it’s tough to see standardization. However, Sony, Panasonic, Samsung, and thirteen other companies are banding together to focus on a single universal type of active shutter glasses. For technology that’s still in a wild phase, this seems pretty promising.

Disadvantages

May require expensive hardware upgrades

Glasses are expensive, and require charging

Cheap setups can cause “ghosting”

Can cause headaches

There are plenty of disadvantages here, since the technology is new. First, if you’re on older hardware, you’ll need a major upgrade. If you have a really recent NVidia card, then you might be able to enable active shutter 3D if you have glasses and updated drivers. Most people, however, will need to get a new graphics card at the very least.

If your TV is based on active shutter, you obviously won’t need the upgrade, but this is still going to be expensive. The next problem is that the glasses are expensive. Really expensive. Cheap sets can be around $50, and most manufacturers sell their glasses for $100-150. If you want to have a family-friendly home theater experience, you can easily pay an extra $400 dollars on top of the TV to get it. And, for that extra money, you’re getting glasses that are only good for so long on a charge. Yes, these glasses have a battery pack that needs to be charged, and you can only watch so much on a single charge. Some people also complain about the weight and comfort level of the glasses, and this can definitely weight in on headaches. More on that in a bit.

Another issue is that if you’ve skimped on either of the above points, the shutter rate on the glasses can go ever-so-slightly out of sync with the video, causing “ghosting.” It’s an effect where you see a bit of the other image that you shouldn’t see and really kills the 3D effect and image quality. This can also happen as the battery discharges on you glasses. This isn’t limited to active shutter 3D – passive can face this, too – but it’s definitely more pronounced.

Not all active shutter glasses are unsightly and impractical. These are the SSG-3700CR’s by Samsung, and they even have a wireless charging capability.

The last issue is a really big one. Many people complain of headaches after watching 3D via active shutter for an extended period of time. 3D in general, regardless of the type, is prone to giving people headaches because it’s a trick of the brain. Your eyes see the TV, but to focus on the 3D image, they have to focus on a plane that’s much closer, maybe half the distance or less. This is even shorter for monitors. Now, compound this with the equivalent of a rapid-moving eye-patch, and you can get headaches pretty quickly.

After some research on the web, there are a lot of anecdotal reports that estimate 2-3 hours before this happens. Some people can’t last more than an hour, while others have very few problems. This is the reason why you can’t just demo a 3D TV for a few minutes and just buy it. It’s much better if you have a friend who has one where you can watch one for a while. On the whole, monitors aren’t very different. Ghosting is a bit more prominent, mostly when your system lags, and it’s a bit of a trade-off between your image quality and being ghost-free. For what it’s worth, active shutter based monitors are probably more worthwhile than TVs. It’s a more personal experience by nature, so you’re less likely to need to buy more 3D glasses and you can control the experience better with your computer.

Glasses-Free

Autostereoscopic displays, also known as “glasses-free” displays, are very new on the market. There are a few different ways these TVs and monitors work.

Parallax Barrier displays, like the Nintendo 3DS, use some kind of barrier with vertically-oriented slits. Some light is blocked by each eye, so they each see a different image. They used to block pixels from the front of the screen, but now they block light from the backlight, which makes the device more energy-efficient and the picture brighter.

Lenticular arrays use lenses to focus each eye on a different portion of the image. Both of these types rely on proper positioning by the viewer. You’d have to sit in a good place for the 3D effect to work, and if you move too much, you’ll lose it.

A third type uses a camera to actively track where viewers are in the room, and can adjust the picture accordingly. Surprisingly, there are some TV’s that can do this for up to three people, but these models are expensive and not mainstream yet.

Advantages

No glasses!

That’s pretty much it (aside from the 3D itself, of course).

Disadvantages

Adjustments have to be made, either on TV/monitor/device or on seating

Limited number of viewers due to limited viewing angle

Picture distortion

First and foremost, this technology requires tweaking to get just right. It’s easy enough with something like the Nintendo 3DS – there’s a slider to adjust the focal length – but with large TV in a home theater, it’s more complicated. You have limited viewing angles, and so you have to adjust seating if you can’t adjust the TV or monitor. Also, if you move or fidget a lot, you’ll find that you’ll lose the 3D effect often. That can be a problem with the 3DS, since it’s a handheld device, but it can also be a problem on many TVs. You’ll find that you can’t just plop yourself on the couch in every which way and have it “just work.” Not necessarily a deal breaker on its own, but there are other drawbacks to consider.

As we just said, you have limited viewing angles. That means limited viewers, because you can only have so many people in the same spot. Even when you have a camera, the usually maximum number of people that can be tracked is three. Keep this in mind if you’re on the market for a TV.

Lastly, there’s an element of picture distortion. Many people report dark bands running down the screen, which makes sense considering how parallax barrier displays work. Even with the change in technology we mentioned above, it’s far from perfect. In addition, since the effect is produced by blocking light in one direction, sometimes things in the background will appear distorted and stretched out in ways they shouldn’t be.

Content and Providers

Just like HDTV, 3D TVs are pretty much useless unless you have content to watch in 3D. Since 3D channels are comparatively few and far-between, you may not get as much use out of your TV as you think. Be sure to check and see if your content provider has 3D channels available, and think about whether you’re willing to pay the extra amount monthly for them. Real 3D is where it’s at, and this applies to streaming and Blu-ray, too. While 3D is picking up, there’s not enough worthwhile media out there – yet.

To make up for this fact, many TVs and monitors do offer a 3D conversion capability. In this process, the incoming video is analyzed and specific objects are identified and have an added or removed depth. While this seems nice, it really isn’t that great. Any converted content seems like a cheap knock-off of native 3D content, no matter how good it seems. And, while the technology does work well for many things – RTS games like StarCraft 2, for example – it does not work for everything. And, you never know how it’ll be, since every company does their conversion process differently, which in turn affects your various media sources differently.

A great way to point out the difference is with a few movies. While James Cameron’s Avatar is an example of native 3D, The Clash of the Titans is an example of 2D converted to 3D. The process has gotten better since then – The Immortals was converted and looks much better than Clash – but it’s still not as solid as native 3D.

Lastly, native 3D has different formats. Most devices will work with more than one, and some will have to convert between them. On the whole, you don’t have to worry about it too much, it seems, but it’s worth pointing out that there’s no single standard yet.

Emerging Technologies and Mold-Breaking Products

3D technology is still being aggressively developed. We’ve had the chance to check out a few specific models that took things to the next step. More importantly, they both show some important trends to watch for, in case you decide to hold off on your 3D display purchase.

LG D2342P

We got a chance to spend some real quality time with this monitor, courtesy of LG (as a reminder, they did sponsor us at BlizzCon 2011). This seems like a standard 23” 1080p 3D monitor, but there a few key things that really set it apart. This particular display (among others that are planned for release) uses passive 3D technology. But, instead of the usual linear polarization, this display uses circular polarization. The effect is supposed to dramatically reduce the dimness that’s typical of passive 3D technology. In practice, video was about 50% brighter, at least to our eyes, and the LED-backlighting in the display also helped with that. This is actually how 3D using the RealD Cinema system does it in theaters, so those glasses would be compatible.

The other tweaks that LG brought to this display are more subtle, but definitely indicate things are going forward. First, it uses HDMI 1.4, so if you want to plug in an XBOX 360 or a PS3, you should have no problems. Second, LG very graciously developed clip-ons for those of us who were eyeglasses. No more struggling to fit 3D glasses over your normal ones!

These clip right on, and can flip up as well. It’s a small touch, but ones that’s really appreciated. LG told us they’d include a pair with the monitor, but the press release says they include normal glasses. In either case, both types of eyewear can be bought for about $10 apiece.

LG’s touting its conversion process that would work automagically with everything. We actually played the new Starcraft 2 expansion for over an hour at BlizzCon. The conversion process was actually pretty good with it. Obviously, some things work better than others – for example, text is horrendous in combination with the 3D effect – but the overall experience was at the low-end of the top tier. And, there’s no computer software for adjustment; everything is done on the monitor through the settings menu.

As far as native 3D goes, things looked great, and were pretty solid. The display also allows for three different kinds of 3D depending on what format you’re using, so you know there’s at least some compatibility.

Lastly, and perhaps most importantly, is the price point. LG’s been trying to aggressively push this, and the MSRP of the D2343P is $349. That being said, LG told us they’ve been running a promo and it was online for $299 in most places, and Amazon even has it for as low as $264. Put another way, the price difference between this monitor and another quality 23” LED monitor (say, the Asus VS247H-P) is less than $80. That $80 gets you 3D with conversion and a pair of glasses. It’s not quite impulse-buy territory, but when the premium for quality 3D is that low, the temptation is strong.

The drawbacks are few, but prominent. Ghosting definitely occurs, and while subtle at times, it’s more frequent than we’d like. Secondly, we’d still worry about how well this would work with games on the whole, and specifically with online games on the PS3 and Xbox 360. There’s a small delay while converting the video, and small delays can translate into instant deaths with games like FPSs. On the whole, it’s not perfect, but it is a nice package, and it’s very attractive because of the comparatively low price.

The Verge did a great review on it here. It’s a glorious 55” TV that works similarly to Lenticular Array Glasses-Free. However, it also combines facial tracking to achieve it right, and allows up to nine simultaneous viewing angles. That blows everything else out of the whatever. Oh, and did we mention that it’s in HD? Not your regular 1080p, either. This thing is in 4K2K – 3840×2160, 4x the current norm of 1920×1080. The Red cams that have been sweeping movie production lately can shoot natively at or very close to that resolution. Can you imagine watching a movie at the resolution it was filmed in? That, too, 4x the current norm?

Of course, it also has a 3D conversion engine built-in, but the feature we really like is the ability to change the depth (not just for focus, but for the overall effect) of the 3D. It’s much more customizable than many other glasses-free TVs out there. You can read more in the press release (pdf).

There are, of course, drawbacks. While the picture is really bright and really high-quality, it does show some of those black vertical striations we mentioned in the Glasses-Free section above. And, as you may expect, the price is crazy. It’s estimated to cost about €7,999 when it releases sometime in December. It’s definitely worth checking out though; it’s quite an experience.

LG’s Dual Play

One very interesting feature that LG has made possible with its passive 3D tech is “Dual Play.” Using modified glasses, two people can play a multiplayer game without using a split-screen setup. Instead of each pair of glasses having one lens for the left eye image and one lens for the right eye image, one pair has both lenses that can see the left eye image, and the other pair for the right eye image. (Now you know how to make your own, if you don’t want to buy them!) Each player gets a full-screen 2D image, and neither player sees the other’s screen. Many of LG’s Cinema 3D TVs are capable of this, and games will work with this automatically by just activating the proper setting on the TV. Of course, they can take better advantage of the feature by offering built-in support.

In terms of the experience, you do get some ghosting of the other person’s screen. At the same time, playing Halo CE with another person in full-screen is still awesome. It’ll be interesting to see if this kind of technology can become a wide standard.

Sony’s HMZT1 Personal 3D Viewer

The future is here. Sony has made possible – albeit at $800 – a personal 3D viewer, straight out of science fiction. Here’s a fun game: try and name as many sci-fi series as you can in 30 seconds these.

In any case, The Verge has yet another great review for these, but here’s a summary. The integrated headphones aren’t great, and there’s no aux input so you can’t swap them out. The unit’s front-heavy, so it can get uncomfortable after a few hours of use. The lenses in front of the tiny 720P screens are a real pain to get positioned just right. But, the picture is fantastic, natural, and completely personal. And, there’s a DIY virtual reality hack already out there for it.

It’s not really practical and there’s plenty of things that need to be changed, but Sony’s shown that it’s definitely possible. In an iteration or two, this could really be something stupendous.

Final Thoughts

Everything comes down to what you prefer. We can’t stress enough how important it is for you to be out there and see this stuff for yourself. Or, alternatively, make sure there’s a good return policy from you favorite online store. Things that might not bother you while watching for 15 minutes may drive you crazy after 2 hours. And, if you’re in the stores, make sure the sales people have it on the right channel. Many people report that the cheaper/sale models are set to standard definition channels to throw off uneducated buyers and persuade them towards the more expensive models.

We already have the HTG Guide to HDTV Technology, as well as how to pick the right PC monitor, and both of those guides still largely hold true. The one exception is that many monitors – especially 3D-enabled ones – are using HDMI as a standard connector now instead of DVI. HDMI 1.4 is backwards-compatible with normal content, but is required for 3D content. That includes playing 3D content using your PS3 and/or Xbox 360. You’ll also need to use an HDMI 1.4-compatible cable, and since this is all digital, don’t waste your money on expensive brands.

And, whether or not your agree on active shutter, passive, or glasses-free tech, I think we can all agree that they’re all better than these: